Procedure for replacing the knives of a disc chipper

Abstract

A knife (12), a holding and releasing mechanism (8) are oriented in the direction of a radius of a chipper disc (19). The holding and releasing mechanism (8) is pushed in the direction of the radius of the chipper disc to release the knife (12) and drawn in the opposite direction to fasten the knife in the chipper disc (19). A power unit (32) with reciprocable spindle (34) selectively engages a holding element (11) of the holding and releasing mechanism (8) to release the knife (12) from the chipper disc (19). A device (36) can be provided for automatically positioning the holding and releasing mechanism (8) to lie opposite the spindle (34) of the power unit (32). The time consumed in replacing the knives is reduced and laborious manual operations can be avoided. The procedure can be automated.

I claim: 
     
       1. A procedure for replacing a knife in a chipper disc of a disc chipper comprising the steps of: providing a chipper disc comprising a knife assembly with at least one knife and a holding and releasing mechanism, the at least one knife being firmly attached in the chipper disc and the knife assembly and being oriented generally in a radial direction in the chipper disc;   loosening the at least one knife be moving the holding and releasing mechanism in a first direction, the first direction generally being along a radius of the chipper disc;   removing the at least one knife from the chipper disc;   inserting a new knife for the removed at least one knife; and   fastening the new knife in the chipper disc by moving the holding and releasing mechanism in a second direction, the second direction being opposite to the first direction.   
     
     
       2. The procedure according to claim 1, wherein during the step of fastening, moving of the holding and releasing mechanism is generated by an element placed between the holding and releasing mechanism and the chipper disc. 
     
     
       3. The procedure according to claim 2, further comprising the step of rotating the chipper disc to generate a centrifugal force and wherein during the step of fastening, moving of the holding and releasing mechanism is further generated by the centrifugal force being applied to the holding and releasing mechanism. 
     
     
       4. The procedure according to claim 1, wherein during the step of loosening, moving of the holding and releasing mechanism is generated by a power element placed adjacent the holding and releasing mechanism and the chipper disc. 
     
     
       5. The procedure according to claim 1, further comprising the step of rotating the chipper disc to generate a centrifugal force and wherein during the step of fastening, moving of the holding and releasing mechanism is generated by the centrifugal force being applied to the holding and releasing mechanism. 
     
     
       6. The procedure according to claim 1, further comprising the step of: providing a spring between the holding and releasing mechanism and the chipper disc;   rotating the chipper disc to generate a centrifugal force; and   urging the holding and releasing mechanism in the second direction by at least one of the centrifugal force from rotation of the chipper disc and by urging force of the spring.   
     
     
       7. The procedure according to claim 6, wherein during the step of loosening, moving of the holding and releasing mechanism occurs during non-rotation of the chipper disc and overcomes the urging of the spring.